EP1456029A1

EP1456029A1 - Infrared-reflective, transparent, multi-layer plastic laminates

Info

Publication number: EP1456029A1
Application number: EP02792819A
Authority: EP
Inventors: Rüdiger Gorny; Siegfried Anders; Wolfgang Nising
Original assignee: Bayer MaterialScience AG
Current assignee: Covestro Deutschland AG
Priority date: 2001-12-10
Filing date: 2002-11-27
Publication date: 2004-09-15
Anticipated expiration: 2022-11-27
Also published as: US6841240B2; EP1456029B1; WO2003053689A1; RU2004121157A; AU2002358554A1; JP4653396B2; KR100966688B1; KR20040070212A; DE10160569A1; CN100575070C; CN1703316A; IL162234A0; AU2002358554B2; BR0207156B1; CA2469636A1; JP2005512856A; MXPA04005573A; DE50207884D1; US20030148093A1; BR0207156A

Abstract

Laminate comprises a layer A containing a base material selected from a transparent thermoplastic plastics material (I) and a lacquer and UV absorber(s), a layer B containing (I) and colorant(s) and a layer C containing (I). Independent claims are also included for the following: (1) Production of the laminate by coextrusion of layers A, B and C; (2) Production of the laminate by applying layer A by lacquering to a substrate comprising layers B and C.

Description

: IR-REFLECTIVE, TRANSPARANT MULTILAYER PLASTIC LAMINATES

The invention relates to a multilayer product made of plastic with high IR reflection and high gloss.

Multi-layer products with layers that contain transparent thermoplastic materials are known.

Polycarbonate sheets in particular are known. These are provided for a variety of applications. They are produced, for example, by extruding compositions containing polycarbonate (molding compositions) and, if appropriate, coextruding with molding compositions which contain an increased proportion of UV absorbers.

Polycarbonate sheets are known from EP-A 0 110 221.

For the long-term protection of polycarbonate sheets against yellowing by UV light, EP-A 0 320 632 teaches that the sheets are to be equipped with a coextrusion layer which contains low-volatility UV absorbers in increased concentrations.

EP-B 0 678 376 and EP-B 0 595 413 teach that for plates made of polyesters, in particular for plates made of copolyesters of aromatic dicarboxylic acids and mixtures of two aliphatic diols such as e.g. PETG, weather protection is achieved by coextrusion with cover layers that contain UV absorbers e.g. based on benzotriazoles in increased concentrations.

From the German patent DE-C 25 44 245 a table made of polymethyl methacrylate with a content of light-reflecting particles which are aligned parallel to the surface is known. Their layer thickness is dimensioned in such a way that visible light can largely pass through and largely reflect infrared radiation. The known body contains the light-reflecting particles in the base material made of polymethyl methacrylate. They are introduced into the liquid methyl methacrylate monomer, this is poured into a polymerization chamber formed from glass plates arranged in parallel and partially polymerized. Up to this point the particles have sunk onto the lower glass plate. By parallel displacement of this plate, the particles are aligned parallel to the surface and held in this position as the polymerization continues. This treatment stage makes the manufacturing process complex and expensive.

EP-A 340 313 describes solar radiation-resistant coatings for ships, tanks, buildings and the like in order to reduce their heating in the sun. The coatings contain a binder, a heat-reflecting pigment and optionally any color pigments.

According to EP-A 428 937, polyethylene sheets for greenhouses are provided with a coating by brushing or spraying, which contains light-reflecting pigments in a matrix of a paint binder. Since the pigment particles are not oriented by the application process, they only have a shading effect and result in unsatisfactory transmission, which is more common due to the low level of adhesion

Lacquer binders on polyethylene can be easily washed off the coated web with a water jet.

EP-A 0 548 822 describes PMMA sheets and polycarbonate sheets which contain special pearlescent pigments in the coextrusion layer. These pearlescent pigments consist of a carrier material, e.g. made of mica, which is covered with a 60 to 120 nm thick titanium dioxide layer.

The production of these pearlescent pigments is described, for example, in DE-A 196 18 569. EP-A 0 548 822 teaches that a selectivity index (SKZ) of over 1.15 is required in order to achieve sufficient IR reflection. The SKZ is defined as follows.

The quotient T / g is also called the selectivity index SKZ (according to DIN 67 507). This is understood as the quotient from the percentage of light transmission in the visible range and the percentage of total transmittance for radiation energy. The SKZ is a measure of IR reflection and therefore also of the effectiveness of sun protection glazing; it should therefore be as high as possible.

It is known that the plates described in EP-A 0 548 822 contain 20 to 40% by weight of the pearlescent pigments in the coextrusion layer in order to achieve the required high selectivity indicators. It is disadvantageous that such a high proportion of the pearlescent pigment is required. This makes the plates very expensive.

DE-A 100 06 651 teaches that pearlescent pigments with three or more layers of titanium dioxide and silicon dioxide on mica in the weathering of plastics containing these pigments bring about a particularly low yellowing in weathering.

Pearlescent pigments have the disadvantage that they result when used in an outer layer of a multilayer ^'to produce a matte surface. A high proportion of pearlescent pigments is also required.

The present invention is therefore based on the object of providing IR-reflecting products with selectivity indicators (SKZ) greater than 1.15, the surface of which has a high luster and which make do with the smallest possible amounts of pearlescent pigment.

This problem is solved by a multi-layer product comprising three

Layers A, B and C, where layer A is a transparent thermoplastic Contains plastic, and wherein layer B contains a transparent thermoplastic and a pigment, which consists of a transparent carrier material and an overlying 150 to 200 nm thick titanium dioxide layer, and wherein layer C contains a transparent thermoplastic and wherein over the titanium dioxide Layer further layers can be applied. This multilayer product is the subject of the present invention.

The skilled worker can optimize the concentration of the pigment in routine experiments. He will choose the concentration so that the SKZ is greater than 1.15. The concentration naturally also depends on the thickness of layer B.

If additional layers are applied over the titanium dioxide layer, these should be selected so that they do not prevent the SKZ from exceeding 1.15.

A particular embodiment of the present invention is the multilayer product mentioned, layer B being 15 to 250 μm thick.

Another particular embodiment of the present invention is the said multilayer product, the transparent thermoplastic material which is contained in layers A, B and C being selected from the group consisting of polycarbonate, polymethyl methacrylate, modified PMMA (these are copolymers from methyl methacrylate and butyl methacrylate or butyl acrylate or other common comonomers), transparent ABS, polystyrene, styrene-acrylonitrile copolymer, transparent PVC and polyester, in particular those with repeating units derived from ethylene glycol and / or cyclohexanedimethanol and / or butylene glycol and terephthalic acid and / or isophthalic acid and mixtures thereof.

Another particular embodiment of the present invention is the multi-layer product mentioned, the transparent thermoplastic plastic being at least one of the layers A, B and C a copolyester derived from Dicarboxylic acids and diols, the dicarboxylic acids being selected from the group consisting of terephthalic acid, isophthalic acid and cyclohexane-1,4-dicarboxylic acid and the diols being selected from the group consisting of ethylene glycol, cyclohexanedimethanol and diethylene glycol, and wherein the repeating units , which are derived from diethylene glycol, have a proportion of all repeating units derived from diols of less than 5 mol%.

Cyclohexanedimethanol has the following structure:

Another particular embodiment of the present invention is said multilayer product, wherein layer B lies between layers A and C.

Another particular embodiment of the present invention is the said multilayer product selected from the grapple consisting of plates, solid plates, corrugated plates and multi-wall sheets.

The present invention furthermore relates to the use of the multilayer product according to the invention for the production of decorative panels for

Wall cladding, partition walls, ceiling cladding, false ceilings, glazing for greenhouses, glazing for conservatories, glazing for bus stops, roofing, glazing with subdued light, or for the replacement of paint coats and for thermal insulation.

The present invention furthermore relates to a product comprising the multilayer product according to the invention.

This product is preferably selected from the group consisting of wall cladding, partition wall, ceiling cladding, false ceiling, glazing for greenhouses, glazing for conservatories, glazing for bus stops, roofing, glazing with subdued light, replacement product for painting.

In addition to layers A, B and C, the multilayer product according to the invention can contain further layers. The order of the layers is arbitrary. It is preferred that layer B is between layers A and B. Further preferred orders of layers A, B and C are the following: C-B-A-C or C-B-A-B-C or C-B-A-B.

Layers A and B and C can each consist of different plastics. If several layers of similar layers occur (such as in C-B-A-B-C), the similar layers (in the example twice B and twice C) can consist of different compositions.

The pigment according to the invention consists of a transparent carrier material which is coated with a 150 to 200 nm thick titanium dioxide layer. Pigments of this type are known and are commercially available. Pigments with a disk-like shape with a diameter of 1 to 80 μm and a thickness of 0.4 to 2.0 μm are preferred

The transparent carrier material is mica, another layered silicate, glass platelets, PbCO ₃ x Pb (OH) and BiOCl in platelet form or platelet-shaped silicon dioxide, produced by the process described in WO 93/108237.

The multilayer product according to the invention has the advantage of having a selectivity index greater than 1.15 and a surface with high gloss (preferably> 40%, particularly preferably> 70%). Only a small amount of the pigment according to the invention is required. The multilayer products according to the invention can be used as heat protection glazing.

Layer B of the multilayer product according to the invention is preferably 15 to 250 μm, in particular 20 to 150 μm, and very particularly preferably 25 to 70 μm, thick.

Layer C of the multilayer product according to the invention is preferably 5 to 1000 μm thick.

The transparent thermoplastic which is contained in layers A, B and C of the multilayer product according to the invention is preferably selected from the group consisting of polycarbonate, polymethyl methacrylate, modified PMMA (these are copolymers of methyl methacrylate and butyl methacrylate or butyl acrylate or other common comonomers) , transparent ABS, polystyrene, styrene-acrylonitrile copolymer, transparent PVC and polyester, especially those with repeating units derived from ethylene glycol and / or cyclohexane dimethanol and / or butylene glycol and terephthalic acid and / or isophthalic acid and / or cyclohexane-l, 4-dicarboxylic acid and the like mixtures.

The transparent thermoplastic contained in layers A, B and C of the multilayer product of the invention may also be the polyester disclosed in US-A 5986040. It can also be the plastic composition disclosed in WO 99/63002, it can also be the plastic disclosed in WO 0069945.

Polycarbonate is particularly preferred, in particular homopolycarbonate based on bisphenol A.

In order to increase the weather resistance of the multilayer products according to the invention, both the top layer and the middle layer can UN absorber included. This can be present in different amounts in the different layers.

The multilayer product according to the invention can be produced by coextrusion, melt lamination, painting or laminating. Coextrusion is preferred.

Layer C of the multilayer product according to the invention can additionally contain UN absorbers, thermal stabilizers, optical brighteners, dyes and other additives.

Layer C may additionally contain 0 to 5% by weight of the pigment contained in layer B.

Layers A, B and C can, independently of one another, additionally use UN absorbers,

Contain thermal stabilizers, optical brighteners, dyes and other additives.

The multilayer products according to the invention can in particular be solid plastic sheets, corrugated sheets and multi-wall sheets (e.g. double wall sheets, three-wall sheets, corrugated multi-wall sheets). The plates also include those which have an additional covering layer with a molding compound with an increased UN absorber content on one or both sides.

The multilayer products according to the invention have pearlescent surfaces. They can therefore be used as decorative panels for wall coverings, partitions,

Ceiling cladding, false ceilings, glazing and roofing with subdued light, for modern room design, for visually appealing facade cladding, or for the replacement of paint coats and for heat protection. Subsequent processing of the multilayer products according to the invention, such as deep drawing or surface processing, such as finishing with scratch-resistant lacquers, water-spreading layers and the like, are possible, and the products produced by these processes are also the subject of the present invention.

Thermoplastic, aromatic polycarbonates for the coextrusion molding compositions according to the invention or the moldings with which they are coated are those which have also been used hitherto for this purpose. These are homopolycarbonates, copolycarbonates and thermoplastic polyester carbonates. They have average molecular weights M _w of 18,000 to 40,000, preferably from 20,000 to 36,000 and in particular from 22,000 to 35,000, determined by measuring the rel. Solution viscosity of a solution of the polycarbonate in dichloromethane or in mixtures of equal amounts by weight of phenol / o-dichlorobenzene at 25 ° C, calibrated by light scattering.

For the production of polycarbonates for the coextrusion molding compositions according to the invention, see for example "Schnell", Chemistry and Physics of Polycarbonates, Polymer Reviews, Vol. 9, Interscience Püblishers, New York, London, Sydney 1964, on DC PREVORSEK. BT DEBONA and Y. KESTEN, corporate research

Center, Allied Chemical Corporation, Moristown, New Jersey 07960, "Synthesis of Poly (ester) carbonate Copolymers" in Journal of Polymer Science, Polymer Chemistry Edition, Vol. 19, 75-90 (1980), on D. Freitag, U. Grigo, PR Müller, N. Nouvertne, BAYER AG, "Polycarbonates" in Encyclopedia of Polymer Science and Engineering, Vol. 11, Second Edition, 1988, pages 648-718 and finally

Dres. U. Grigo, K. Kircher and PR Müller "Polycarbonate" in Becker / Braun, Plastic Manual, Volume 3/1, Polycarbonate, Polyacetale, Polyester, Cellulose Ester, Carl Hanser Verlag Munich, Vienna 1992, pages 117- 299. Production is preferably carried out using the phase interface process or the melt transesterification process and is described by way of example using the phase interface process. Compounds which are preferably to be used as starting compounds are bisphenols of the general formula HO-Z-OH, in which Z is a divalent organic radical having 6 to 30 carbon atoms and containing one or more aromatic groups. Examples of such compounds are bisphenols which belong to the group of dihydroxydiphenyls, bis (hydroxyphenyl) alkanes, indane bisphenols, bis (hydroxyphenyl) ethers, bis (hydroxyphenyl) sulfones, bis (hydroxyphenyl) ketones and α, α'-bis ( hydroxyphenyl) - diisopropylbenzenes belong.

Particularly preferred bisphenols belonging to the abovementioned compound groups are bisphenol-A, tetraalkylbisphenol-A, 4,4- (meta-phenylenediisopropyl) diphenol (bisphenol M), 4,4- (para-phenylenediisopropyl) diphenol, l, l- Bis- (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (BP-TMC) and, if appropriate, their mixtures. Homopolycarbonates based on bisphenol-A and copolycarbonates based on the monomers bisphenol-A and l, l-bis- (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane are particularly preferred. The bisphenol compounds to be used according to the invention are reacted with carbonic acid compounds, in particular phosgene, or diphenyl carbonate or dimethyl carbonate in the melt transesterification process.

Polyester carbonates are obtained by reacting the bisphenols already mentioned, at least one aromatic dicarboxylic acid and optionally carbonic acid equivalents. Suitable aromatic dicarboxylic acids are, for example, phthalic acid, terephthalic acid, isophthalic acid, 3,3'- or 4,4'-diphenyldicarboxylic acid and benzophenone dicarboxylic acids. A part, up to 80 mol%, preferably from 20 to 50

Mol% of the carbonate groups in the polycarbonates can be replaced by aromatic dicarboxylic acid ester groups.

Inert organic solvents used in the interfacial process are, for example, dichloromethane, the various dichloroethanes and chloropropane compounds, carbon tetrachloride, trichloromethane, chlorobenzene and chlorotoluene. chlorobenzene or dichloromethane or mixtures of dichloromethane and chlorobenzene are preferably used.

The phase interface reaction can be accelerated by catalysts such as tertiary amines, in particular N-alkylpiperidines or onium salts. To be favoured

Tributylamine, triethylamine and N-ethylpiperidine are used. In the case of the melt transesterification process, the catalysts mentioned in DE 4238123 are used.

The polycarbonates can be branched deliberately and in a controlled manner by using small amounts of branching agents. Some suitable branching agents are: phloroglucin, 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) -hepten-2; 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) heptane; 1,3,5-tri- (4-hydroxyphenyl) benzene; 1,1,1-tri- (4-hydroxyphenyl) ethane; Tri- (4-hydroxyphenyl) -phenylmethane; 2,2-bis- [4,4-bis- (4-hydroxyphenyl) cyclohexyl] propane; 2,4-bis (4-hydroxyphenyl-isopropyl) -phenol; 2,6-bis

(2-hydroxy-5'-methyl-benzyl) -4-methyl phenol; 2- (4-hydroxyphenyl) -2- (2,4-dihydroxyphenyl) propane; Hexa- (4- (4-hydroxyphenyl-isopropyl) phenyl) orthoterephthalic acid ester; Tetra (4-hydroxyphenyl) methane; Tetra- (4- (4-hydroxyphenyl-isopropyl) phenoxy) methane; α, α ', α "-Tris- (4-hydroxyphenyl) - 1, 3, 5-triisopropylbenzene; 2,4-dihydroxybenzoic acid; trimesic acid; cyanuric chloride; 3,3-bis- (3-methyl-4-- hydroxyphenyl) -2-oxo-2,3-dihydroindole; 1,4-bis (4 ', 4 "-dihydroxytriphenyl) methyl) benzene and in particular: l, l, l-tri- (4-hydroxyphenyl) - ethane and bis (3-methyl-4-hydroxyphenyl) -2-oxo-2,3-dihydroindole.

The 0.05 to 2 mol% optionally to be used, based on the amount used

Diphenols, on branching agents or mixtures of the branching agents, can be used together with the diphenols but can also be added at a later stage in the synthesis.

Preferred chain terminators are phenols such as phenol, alkylphenols such as

Cresol and 4-tert-butylphenol, chlorophenol, bromophenol, cumylphenol or their Mixtures used in amounts of 1-20 mol%, preferably 2-10 mol% per mol of bisphenol. Phenol, 4-tert-butylphenol and cumylphenol are preferred.

Chain terminators and branching agents can be added to the syntheses separately or together with the bisphenol.

The preparation of the polycarbonates for the coextrusion molding compositions according to the melt transesterification process is described by way of example in DE 4 238 123.

The UV absorbers are incorporated into the thermoplastic coextrusion molding compositions to be used according to the invention by customary methods, for example by mixing solutions of the UV absorbers with solutions of the plastics in suitable organic solvents such as CH ₂ C1, haloalkanes, halogen aromatics, chlorobenzene and xylenes. The substance mixtures are then homogenized in a known manner via extrusion; the solution mixtures are removed in a known manner, for example compounded, by evaporation of the solvent and subsequent extraction.

Suitable stabilizers for the polycarbonates for the coextrusion molding compositions according to the invention are, for example, phosphines, phosphites or epoxides or Si-containing stabilizers and further compounds described in EP 0 500 496 A1 and US Pat. No. 3,673,146. Examples include triphenylphosphines, diphenylalkylphosphites, phenyldialkylphosphites, tris (nonylphenyl) phosphite, tetrakis (2,4-di-tert-butylphenyl) -4,4'-biphenylene-diphosponite and triarylphospb.it. Triphenylphosphine and tris (2,4-di-tert-butylphenyl) phosphite are particularly preferred.

The coextrusion molding compositions according to the invention can be used for the coextrusion of plates. These panels can be provided with coex layers on one or both sides. Coextrusion as such is known from the literature (see for example EP 110 221 and EP 110 238).

Suitable UV absorbers for the coextrusion materials to be used, if any, are those compounds which, owing to their absorption capacity below 400 nm, are able to effectively protect polycarbonate from UV light and have a molecular weight of more than 370, preferably 500 and more ,

Suitable UV absorbers are in particular the compounds of the formula (II) described in WO 99/05205

wherein

R ¹ and R ^{2 are the} same or different and

H, halogen, Ci-Cio-alkyl, C ₅ -Cι ₀ cycloalkyl, C ₇ -Cι ₃ aralkyl, C ₆ -Cι ₄ aryl, -OR ⁵ or - (CO) -OR ⁵ mean with R ⁵ = H or Ci-Q-alkyl,

R ³ and R ^{4 are} likewise the same or different and denote H, -C ₄ alkyl, C ₅ -C ₆ cycloalkyl, benzyl or C ₆ -C ₄ aryl,

1, 2 or 3 and n is 1, 2, 3 or 4, as well as those of the formula (III)

where the bridge

O O

II - (CHR ³ ) - C- -O- (YO) - -c- - (CHR ⁴ ) _C

means

R, ι, R, m and n have the meaning given for formula (II),

wherein p is also an integer from 0 to 3,

q is an integer from 1 to 10,

Y -CH ₂ -CH ₂ -, - (CH ₂ ) ₃ -, - (CH ₂ ) ₄ -, - (CH ₂ ) ₅ -, - (CH ₂ ) ₆ -, or CH (CH ₃ ) -CH ₂ - is

and

R> 3 "and _{J n} R4 have the meaning given for formula (II). Other suitable UN absorbers are those which are substituted triazines, such as 2,4-bis (2,4-dimethylphenyl) -6- (2-hydroxy-4-n-octyloxyphenyl) -l, 3,5-triazine ( CYASORB® UN-1164) or 2- (4,6-diphenyl-l, 3,5-triazin-2-yl) -5- (hexyl) oxy-phenol (Tinuvin® 1577). Particularly preferred as a UN absorber is 2,2-methylenebis (4- (l, l, 3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), which is commercially available under the name Tinuvin® 360 or Adeka Stab ^® LA 31 is sold. The UN absorbers mentioned in EP 0500496 AI are also suitable. The UN absorber Uvinul 3030 from BASF AG obtained in WO 96/15102, Example 1 can also be used.

Examples of antistatic agents are cationic compounds, for example quaternary ammonium, phosphonium or sulfonium salts, anionic compounds, for example alkylsulfonates, alkylsulfates, alkylphosphates, carboxylates in the form of alkali metal or alkaline earth metal salts, nonionic compounds, for example polyethylene glycol esters, polyethylene glycol ethers, fatty acid amines, fatty acid esters, fatty acid esters ,

Preferred antistatic agents are nonionic compounds.

Preferred fillers are glass fibers, mica, silicates, quartz, talc, titanium dioxide or wollastonite. Preferred reinforcing materials are glass or carbon fibers.

All of the starting materials and solvents used for the synthesis of the molding compositions according to the invention can be contaminated with corresponding impurities from their production and storage, the aim being to work with starting materials which are as clean as possible.

The individual constituents can be mixed in a known manner both successively and simultaneously, both at room temperature and at elevated temperature.

The additives are incorporated into the molding compositions according to the invention in a known manner by mixing polymer granules with the additive (s) and other closing extrusion or by mixing the solutions of polycarbonate with solutions of the additives and subsequent evaporation of the solvents in a known manner. The proportion of additives in the molding compound can be varied within wide limits and depends on the desired properties of the molding compound. The total proportion of additives in the molding composition is approximately up to 40

% By weight, preferably 4 to 30% by weight, based on the weight of the molding composition.

The polymer compositions obtained in this way can be converted into shaped objects, such as toy parts, but also fibers, foils, tapes, plates, vessels, tubes and other profiles, using the customary methods, such as hot pressing, spinning, extrusion or injection molding. The polymer compositions can also be processed into cast films. The invention therefore further relates to the use of the polymer compositions according to the invention for the production of a shaped article. The use of multilayer systems is also of interest.

The invention is further illustrated by the following example without being restricted thereto.

example

10 mm twin-wall sheets A, B, C and 16 mm triple-wall sheets D and E, as they are described for example in EP-A 0,110,238 (referred to therein as multi-layer hollow chamber plastics panel) were obtained from the following molding composition: As the base material Makrolon ^® 1243 (branched Bisphenol-A polycarbonate from Bayer AG, Leverkusen with a melt flow index (MFR) according to ISO 1133 of 6.5 g / 10 min at 300 ° C and 1.2 kg load). This was coextruded with the compounds given in Table 1 based on Makrolon ^® 3108 (linear bisphenol-A polycarbonate from Bayer AG, Leverkusen with a melt flow index (MFR) according to ISO 1133 of 6.5 g / 10 min at 300 ° C and 1 , 2 kg load). The thickness of the middle coex layer was approximately

60 microns and the thickness of the outer ^' layer about 45 microns.

The machines and apparatus used to manufacture the multilayer multi-wall sheets are described below:

The facility consisted of:

the main extruder with a screw of length 33 D and a diameter of 70 mm with degassing - the coex adapter (feed block system) two coextraders for applying the intermediate layer and the top layer, each with a screw of length 25 D and a diameter of 30 mm with the special slot die 350 mm width the calibrator - the roller conveyor of the take-off device the cutting device (saw) the storage table.

The polycarbonate granulate of the base material was fed to the hopper of the main extrader, the UV coextrusion material that of the respective coextrader.

The respective material is melted and conveyed in the respective plasticizing system cylinder / screw. Both material melts were brought together in the coex adapter and formed a composite after leaving the nozzle and cooling in the calibrator. The other facilities were used for transporting, cutting to length and depositing the extruded sheets.

The plates obtained were then subjected to a colorimetric evaluation. The following measurement methods were used:

1. The transmission was determined on the basis of the standards ASTM E 308 / ASTM D 1003.

2. The yellowness index was determined in accordance with ASTM E 313.

3. The gloss was determined in accordance with ASTM D 523.

4. The selectivity index was determined in accordance with the DIN 67507 specification.

Coextrusion molding compositions were produced with the formulations mentioned in Table 1 based on Makrolon ^® 3108.

Table 1

The recipes in Table 1 are the compositions of layer B in the examples and the corresponding layers in the comparative examples.

1) - Magna Pearl ^® 1000 from Costenoble GmbH, Eschborn, Germany

2) = Iriodin ^® AC 870 from Merck KGaA, Darmstadt, Germany

3) = Iriodin ^® 9223 from Merck KGaA, Darmstadt, Germany

4) = 2,2'-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol] from Ciba Specialty Chemicals, Lampertheim, Germany

The structure of the pigments is as follows:

In all cases, the core consists of mica.

Magna Pear 1r® 1000:

Thickness of the TiO2 layer over the core: 60-110 nm

Iriodin ^® AC 870:

Thickness of the innermost TiO2 layer above the core: 110-120 nm Thickness of the middle SiO2 layer: 110-140 nm Thickness of the outermost TiO2 layer: 120-150 nm Iriodin ^® 9223

Thickness of the TiO2 layer over the core: 150-200 nm

The batches referred to in Table 1 were coextradiert to 10 mm twin-wall sheets (Table 2) and 16 mm triple-wall sheets (Table 3) in Makrolon ^® 1243rd

Table 2

Table 3

The gloss and the selectivity index were measured on the multi-wall sheets. The results are shown in Table 5.

Table 5

As Table 5 shows, only panels E meet the required profile. The gloss of plates A, B and C is far too low. For plate D, the selectivity index is too low (less than 1.15).

Claims

claims

1. Multilayer product comprising three layers A, B and C, layer A containing a transparent thermoplastic, and layer B a transparent thermoplastic and a pigment consisting of a transparent carrier material and an overlying 150 to 200 nm thick titanium dioxide -Layer consists, contains, and wherein layer C contains a transparent thermoplastic, and wherein further layers can be applied over the titanium dioxide layer.

2. Multi-layer product according to claim 1, wherein layer B is 15 to 250 microns thick.

3. Multi-layer product according to one of claims 1 to 2, wherein the transparent thermoplastic material contained in layers A, B and C is selected from the group consisting of polycarbonate, polymethyl methacrylate, modified PMMA, transparent ABS, polystyrene, styrene -Acrylonitrile copolymer, transparent PVC and polyester.

4. Multi-layer product according to one of claims 1 to 3, wherein the transparent thermoplastic is at least one of layers A, B and C is a copolyester derived from dicarboxylic acids and diols, the dicarboxylic acids being selected from the group consisting of terephthalic acid, Isophthalic acid and cyclohexane-l, 4-dicarboxylic acid and where the diols are selected from the grappe consisting of ethylene glycol, cyclohexane dimethanol and. Diethylene glycol, and wherein the repeat units derived from diethylene glycol account for less than 5 mol% of all repeat units derived from diols. 23 -

5. A multilayer product according to any one of claims 1 to 4, wherein layer B is between layers A and C.

6. Multi-layer product according to one of claims 1 to 5 selected from the grappa consisting of plates, solid plates, corrugated plates and multi-wall sheets.

7. A method for producing the multilayer product according to one of claims 1 to 6 by coextrusion.

8. Use of the multilayer product according to one of claims 1 to 6 for the production of decorative panels for wall cladding, partition walls, ceiling cladding, false ceilings, glazing for greenhouses, glazing for conservatories, glazing for bus stops, roofing, glazing with dim light, or for Replacement of paint coats and for thermal protection.

9. Product containing a multilayer Erzeμgnis according to any one of claims 1 to 6.

10. Product according to claim 9 selected from the grapple consisting of wall cladding, partition wall, ceiling cladding, false ceiling, glazing for greenhouses, glazing for conservatories, glazing for bus stops, roofing, glazing with dimmed light, replacement product for paintwork and product for heat protection.